Question

我正在尝试动态创建"EditText"，在for循环和＆amp;我试图在每个"EditText"上设置一个id，这样我就可以在输入时引用一个特定的id。

到目前为止，这是我的代码 -

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
    Intent intent = getIntent();
    String ss = intent.getStringExtra("input");
    int n = Integer.parseInt(ss);

    EditText[] editTexts = new EditText[n];

    LinearLayout linearLayout = (LinearLayout) findViewById(R.id.linearlayout);
    for (int i = 0; i < n; i++) {
        editTexts[i] = new EditText(this);           
        editTexts[i].setId(i);
        editTexts[i] = (EditText) findViewById(editTexts[i].getId());
        linearLayout.addView(editTexts[i]);

    }
    linearLayout.setPadding(10, 0, 10, 0);

}

应用程序崩溃，我的logcat说 -

10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime: FATAL EXCEPTION: main
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime: Process: com.example.akshatmalviya.fairsharedemo3, PID: 16523
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.akshatmalviya.fairsharedemo3/com.example.akshatmalviya.fairsharedemo3.Main2Activity}: java.lang.IllegalArgumentException: Cannot add a null child view to a ViewGroup
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.ActivityThread.-wrap11(ActivityThread.java)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:102)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:148)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5417)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:  Caused by: java.lang.IllegalArgumentException: Cannot add a null child view to a ViewGroup
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.view.ViewGroup.addView(ViewGroup.java:4077)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.view.ViewGroup.addView(ViewGroup.java:4059)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at com.example.akshatmalviya.fairsharedemo3.Main2Activity.onCreate(Main2Activity.java:34)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.Activity.performCreate(Activity.java:6237)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.ActivityThread.-wrap11(ActivityThread.java) 
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:102) 
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:148) 
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5417) 
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method) 
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
10-23 17:34:01.743 16523-16523/com.example.akshatmalviya.fairsharedemo3 E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

"n"应该是屏幕上创建的EditText的数量，这个n是通过另一个运行良好的活动的意图传递的。请帮帮我。

Answer 1

删除，editTexts[i] = (EditText) findViewById(editTexts[i].getId());当您动态创建EditText时，您不需要在“活动”视图中查找这些内容。

意味着，您在活动xml布局文件中没有动态创建的EditTexts，因此Android无法使用findViewById()方法从View中找到这些EditText。

Answer 2

看看这个问题的答案：

Programmatic Views how to set unique id's?，例如一个是用户“Xiaochao Yang”。

您想使用：

View.generateViewId()

Android - 动态查找视图的ID

2 个答案: